Improvement in derricks



l. THAYER. Derricks. No.l47,5301. Patented Feb. 17, i874..

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ATENT @ruiten JOSEPH THAYER, OF KANSAS CITY, MISSOURI, ASSIGNOR OF ONEHALF HIS'RIG-HT TO HIRAM IV. MCOOTTER, OF SAME PLACE.

IMPROVEMENT IN DERRICKS.

Specification forming part of Letters Patent No. 147,530, dated February 17, 1874; application filed October 29, 1873.

To all whom it may concern:

Be it known that I, JOSEPH THAYER., of Kansas City, county of Jackson and State of Missouri, have invented certain new and useful Improvements in Derrieks, of which the following is a specification:

The object of my invention is an improvement in derricks, whereby the guys may be readily adjusted to compensate for the stretching or varying of the length of the guy-ropes from any cause whatever, and whereby the derrick may be worked and swung around as desired with the least possible force; and to this end my invention consists in providing a hollow gudgeon at the top of the derrick, through which the fall-line of the boom-tackle is passed, so that a direct draft is obtained for adjusting the length of the guy, and this being through the axis of the mast, the derriclr may be swung around without straining the guy or changing the relative position of the boom. My invention also, consists in stepping the mast eccentrically in a wheel or movable base, so that it will automatically swing around in either direction by throwing the foot of the mast ofi' off the center, which is done by turning the base on its center. The weight in this case becomes the operating means to swing the derrick.

teferring to the drawings termin a part of this specification, Figure l is an elevation of the derriek complete, showing, in dotted lines, the hollow gudgeon. Fig. 2 is a section of the upper end of the mast, showing the fall-lines of the guy and hoisting-tackle passing over sheaves or pulleys arranged in a recess in the mast. Fig. 3 is a sectional view of the eccentric stop and movable base; and Fig. 4 is an elevation, showing the movable base in the form of a spur-wheel, and an operatingworm.

Like letters refer to corresponding parts in all of the figures.

A is the mast, having the hollow upper end, as seen at b, and having sheaves or pulleys, an ranged as shown. B is the boom, having its guy-rope leading from a hook or attachment, a, through a block (double or single) at the head ofthe boom 5 thence over a sheave in the mast, and up through the top of said mast, and thence to any point desired or most con venient for operation. The fall-line of the hoisting-tackle also passes over a sheave near the top of the mast, thence down alongside thereof, and then, through the hollow lower end of the mast, over a ixed sheave or pulley, to a windlass or other suitable or convenient operating means. O is the movable base arranged to tiun on a suitable bed or bearing.

The mast A is stepped eccentrically in theV movable part O, as shown at d. A wor1ny screw, D, is arranged to mesh with the cogs on the base C for turning the same, andV thus the mast is thrown from a plumb or vertical position.

The mast being thrown out of plumb, it is obvious that the suspended weight will cause the derrick to swing in either direction as the base is turned one way or the other.

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is y l. The combination, in a derrick, of an eccentrically-stepped mast, A, provided with a hollow gudgeon at its upper end, with the guy rope, booinB, and revolving hook et, substantially as and for the purpose set forth.

2. In a derrick, the combination, with a movable base, of an eccentrically-stepped mast, as

JOSEPH THAYER. l

lvitnesses:

RICHARD ROBERTSON, J. E. HAvENs. 

